1. Field of the Invention
The present invention relates to a string extraction method for an image based on multiple stroke width patterns matching, and more particularly to a string extraction method which can be applied in extracting an license plate number for an automatic recognizing system, a traffic monitoring and a car entrance guard, a container number in a container image, a string in an advertising shop sign, a string in a traffic sign image, a bar code in a bar code image, or a string in a journalism image.
2. Description of the Prior Art
The string extraction of an image is a pre-processing procedure for the string/character recognition, and thus the accuracy thereof will significantly affect the whole performance of the string/character string recognition.
The conventional string extraction for an image is generally processed by calculating the gradient of each pixel, or determining the position of a string based on a computing result of each pixel obtained through an edge detection. However, in these methods, it ignores that not only the gradient or the edge can represent the stroke of each character in the string. Furthermore, the width of each stroke may be different and the width in the same stroke also would have differences according to the size of the picture or the picturing distance.
Thus it can be seen, the prior art described above still has some defects, is not a good design, however, and is urgently to be improved.
Because of the technical defects of described above, the applicant keeps on carving unflaggingly to develop the string extraction method for an image based on a multiple stroke width patterns matching through wholehearted experience and research.